[SPARC64]: Add infrastructure for dynamic TSB sizing.

This also cleans up tsb_context_switch().  The assembler
routine is now __tsb_context_switch() and the former is
an inline function that picks out the bits from the mm_struct
and passes it into the assembler code as arguments.

setup_tsb_parms() computes the locked TLB entry to map the
TSB.  Later when we support using the physical address quad
load instructions of Cheetah+ and later, we'll simply use
the physical address for the TSB register value and set
the map virtual and PTE both to zero.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 95 insertions, 14 deletions

diff --git a/arch/sparc64/mm/tsb.c b/arch/sparc64/mm/tsb.c
index 2f84cef6c1b..dfe7144fcdf 100644
--- a/arch/sparc64/mm/tsb.c
+++ b/arch/sparc64/mm/tsb.c
@@ -9,13 +9,7 @@
 #include <asm/tlbflush.h>
 #include <asm/tlb.h>
 #include <asm/mmu_context.h>
-
-#define TSB_ENTRY_ALIGNMENT	16
-
-struct tsb {
-	unsigned long tag;
-	unsigned long pte;
-} __attribute__((aligned(TSB_ENTRY_ALIGNMENT)));
+#include <asm/pgtable.h>
 
 /* We use an 8K TSB for the whole kernel, this allows to
  * handle about 4MB of modules and vmalloc mappings without
@@ -27,10 +21,10 @@ struct tsb {
 
 extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
 
-static inline unsigned long tsb_hash(unsigned long vaddr)
+static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long nentries)
 {
 	vaddr >>= PAGE_SHIFT;
-	return vaddr & (KERNEL_TSB_NENTRIES - 1);
+	return vaddr & (nentries - 1);
 }
 
 static inline int tag_compare(struct tsb *entry, unsigned long vaddr, unsigned long context)
@@ -51,7 +45,8 @@ void flush_tsb_kernel_range(unsigned long start, unsigned long end)
 	unsigned long v;
 
 	for (v = start; v < end; v += PAGE_SIZE) {
-		struct tsb *ent = &swapper_tsb[tsb_hash(v)];
+		unsigned long hash = tsb_hash(v, KERNEL_TSB_NENTRIES);
+		struct tsb *ent = &swapper_tsb[hash];
 
 		if (tag_compare(ent, v, 0)) {
 			ent->tag = 0UL;
@@ -63,8 +58,9 @@ void flush_tsb_kernel_range(unsigned long start, unsigned long end)
 void flush_tsb_user(struct mmu_gather *mp)
 {
 	struct mm_struct *mm = mp->mm;
-	struct tsb *tsb = (struct tsb *) mm->context.sparc64_tsb;
+	struct tsb *tsb = mm->context.tsb;
 	unsigned long ctx = ~0UL;
+	unsigned long nentries = mm->context.tsb_nentries;
 	int i;
 
 	if (CTX_VALID(mm->context))
@@ -76,7 +72,7 @@ void flush_tsb_user(struct mmu_gather *mp)
 
 		v &= ~0x1UL;
 
-		ent = &tsb[tsb_hash(v)];
+		ent = &tsb[tsb_hash(v, nentries)];
 		if (tag_compare(ent, v, ctx)) {
 			ent->tag = 0UL;
 			membar_storeload_storestore();
@@ -84,6 +80,83 @@ void flush_tsb_user(struct mmu_gather *mp)
 	}
 }
 
+static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_bytes)
+{
+	unsigned long tsb_reg, base, tsb_paddr;
+	unsigned long page_sz, tte;
+
+	mm->context.tsb_nentries = tsb_bytes / sizeof(struct tsb);
+
+	base = TSBMAP_BASE;
+	tte = (_PAGE_VALID | _PAGE_L | _PAGE_CP |
+	       _PAGE_CV    | _PAGE_P | _PAGE_W);
+	tsb_paddr = __pa(mm->context.tsb);
+
+	/* Use the smallest page size that can map the whole TSB
+	 * in one TLB entry.
+	 */
+	switch (tsb_bytes) {
+	case 8192 << 0:
+		tsb_reg = 0x0UL;
+#ifdef DCACHE_ALIASING_POSSIBLE
+		base += (tsb_paddr & 8192);
+#endif
+		tte |= _PAGE_SZ8K;
+		page_sz = 8192;
+		break;
+
+	case 8192 << 1:
+		tsb_reg = 0x1UL;
+		tte |= _PAGE_SZ64K;
+		page_sz = 64 * 1024;
+		break;
+
+	case 8192 << 2:
+		tsb_reg = 0x2UL;
+		tte |= _PAGE_SZ64K;
+		page_sz = 64 * 1024;
+		break;
+
+	case 8192 << 3:
+		tsb_reg = 0x3UL;
+		tte |= _PAGE_SZ64K;
+		page_sz = 64 * 1024;
+		break;
+
+	case 8192 << 4:
+		tsb_reg = 0x4UL;
+		tte |= _PAGE_SZ512K;
+		page_sz = 512 * 1024;
+		break;
+
+	case 8192 << 5:
+		tsb_reg = 0x5UL;
+		tte |= _PAGE_SZ512K;
+		page_sz = 512 * 1024;
+		break;
+
+	case 8192 << 6:
+		tsb_reg = 0x6UL;
+		tte |= _PAGE_SZ512K;
+		page_sz = 512 * 1024;
+		break;
+
+	case 8192 << 7:
+		tsb_reg = 0x7UL;
+		tte |= _PAGE_SZ4MB;
+		page_sz = 4 * 1024 * 1024;
+		break;
+	};
+
+	tsb_reg |= base;
+	tsb_reg |= (tsb_paddr & (page_sz - 1UL));
+	tte |= (tsb_paddr & ~(page_sz - 1UL));
+
+	mm->context.tsb_reg_val = tsb_reg;
+	mm->context.tsb_map_vaddr = base;
+	mm->context.tsb_map_pte = tte;
+}
+
 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 {
 	unsigned long page = get_zeroed_page(GFP_KERNEL);
@@ -92,14 +165,22 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 	if (unlikely(!page))
 		return -ENOMEM;
 
-	mm->context.sparc64_tsb = (unsigned long *) page;
+	mm->context.tsb = (struct tsb *) page;
+	setup_tsb_params(mm, PAGE_SIZE);
 
 	return 0;
 }
 
 void destroy_context(struct mm_struct *mm)
 {
-	free_page((unsigned long) mm->context.sparc64_tsb);
+	free_page((unsigned long) mm->context.tsb);
+
+	/* We can remove these later, but for now it's useful
+	 * to catch any bogus post-destroy_context() references
+	 * to the TSB.
+	 */
+	mm->context.tsb = NULL;
+	mm->context.tsb_reg_val = 0UL;
 
 	spin_lock(&ctx_alloc_lock);